Core



P 1936- E. D. HURT 2,055,899

CORE

Original Filed May 16, 1932 t Fig.1. W 1 r 1 m k 4 VJ 729.2

I. Hurt INVEIVTDR ATTORNEY Patented Sept. 29, 1936 UNITED STATES PATENTOFFICE CORE Ernest D. Hurt, Fort Wayne, Ind., assignor to Phelps DodgeCopper Products Corporation, New York, N. Y., a corporation of Delaware8 Claims.

This application is a refile of my abandoned application Serial No.611,475, filed May 16, 1932.

The invention relates to cores and especially to insulating cores forelectrical coils.

At the present time electrical coils are formed in various shapes otherthan round, the rec tangular or fiat sided shape being commonly used formany purposes. The smaller types of coils, both as to size of core andsize of wire,

are wound on machines adapted to wind a multiplicity of coilssimultaneously. It is essential that each coil have an insulating core,and to provide such core the practice has been to wind on the mandrel asufficient number of turns of paper which shall be common to all thecoils. The several wires are then wound on the core at the selectedpoints to form the coils. When the windings are completed the coils arecut into individuals either before removal from the mandrel or afterthey are removed as a unit.

Where the core is rectangular the wire wound on it exerts considerablepressure upon the corners of the core and frequently causes the sidesthereof to bulge or bow inwardly and thereby destroy the usefulness ofthe coil.

The object of the present invention is to provide a simple, cheap hollowfiat sided core that will maintain its shape in a coil or other articleformed thereon.

The invention consists in the novel combination of parts hereinafterdescribed and illustrated in the accompanying drawing, in which drawingFigure 1 is a plan view of the blank from which the core is formed.

Figure 2 is an edge view of the same.

Figure 3 is a perspective view of the core.

Figure 4 is an end view of a coil with the core therein.

Figure 5 is a side view of the coil partly in section.

I have found by folding a sheet of suitable fibrous material such aswood, into the desired shape, and securing the abutting edges of thesheet together, that a very desirable tube or core is formed which willwithstand the pressure produced at its corners by the wire or othermaterial wound upon it.

In accomplishing the invention I preferably use a thin sheet of wood I,and apply a binder 2 to one side thereof. The binder may be fabric orpaper. I then cut the scorings or angular grooves 3 in the opposite sideof the sheet and at right angles to the grain thereof, the angle of thescorings being preferably 45 for the rectangular core. The scorings areseparated the required distance so that the sections 4 adjacent to themwill form the flat sides of a tube. The opposite side edges 5 are eachbevelled at 45. The wood is substantially cut through at the scores, the5 binder 2 holding the side-forming sections together. Upon folding theblank on the scorings the bevelled walls at each scoring abut and theopposite outer edges 5 abut to form square corners. A tape 6 is appliedover the joint formed 10 by the edges 5 and the tube 1 is thereby heldin shape for winding other material thereon.

In the manufacture of the smaller electrical coils the blank will beformed of such length that it will be common to all the coils to besimul- 15 taneously wound. The blank is wrapped about the mandrel andthe tape 6 is applied to complete the tube. The several windings andinsulation between the layers thereof are then wound on the tube andwhen finished the coils 8 are sep- 20 arated by cutting through theinsulation and the tube either while the unit remains on the mandrel orafter it is removed therefrom.

The cutting of the tube is readily accomplished since it is made withthe grain of the wood. 25

The tube or core 1 in each coil is relatively stiff and retains itsshape and is not appreciably affected by the pressure of the wire woundupon While I prefer to use a suitable form of wood 30 for my hollowcore, any fibrous or other insulating material of suitable form andcapable of resisting the pressure of the material wound upon it willsuffice.

I claim: 35

1. A core for electrical coils formed of a single rectangular blankhaving parallel scorings in one side spaced to define folded wallsections of a tubular core when the core is set up, a binder on theopposite side of the blank and means for se- 40 curing together theabutting edges of the opposite end sections of the blank to lock thewalls in position.

2. A core for electrical coils formed of a wood blank having transversescorings in one side 45 spaced to define folded wall sections when thecore is set up, a binder on the opposite side of the blank and common toall said sections and a member engaging the abutting edges of theopposite end sections of the blank to lock the walls in position.

3. A core for electrical coils formed of a thin wood blank havingtransverse scorings in one side spaced to define folded wall sectionswhen the core is set up, a binder on the opposite side 55 of the blankand common to all the said sections and a tape securing together theabutting edges of the opposite end sections of the blank, to lock thewalls in position.

4. A core comprising side members having bevelled, abutting edges, andan integral outer covering.

5. A core comprising side members having bevelled, abutting edges, andmeans extending over the outer perimeter of the core and united there;

with to form a substantially rigid body.

bevelled, abutting edges, and means forming the outer surface of thecore for retaining said edges in abutting relation.

'7. A core comprising side members having abutting edges, and anadhesive covering over said members forming a core.

8. A core comprising members having abutting edges, means forming a sealbetween said edges, and means for holding said edges in abuttingrelation.

.6. A core comprising side members having Q

